Characteristics of human large granular lymphocytes and relationship to natural killer and K cells

Abstract

Recent evidence, has demonstrated an association between a subpopulation of peripheral blood mononuclear cells, morphologically identified as large granular lymphocytes (LGL), and natural killer (NK) activity. We have now evaluated more directly the role of LGL in both NK activity and antibody- dependent cellular cytotoxicity (ADCC), by using highly enriched populations of LGL, obtained by centrifugation of peripheral blood mononuclear cells on Percoll discontinuous density gradients. Both spontaneous and interferon- augmented NK and ADCC activities were exclusively associated with the LGL- enriched, low density fractions. The majority of LGL formed conjugates with NK-susceptible and antibody-coated target cells. Approximately 20 percent of small conventional lymphocytes also formed conjugates with the target cells for NK, but this was not associated with cytotoxic activity. Virtually all LGL were found to have receptors for the Fc portion of IgG (FcγR). The frequency of LGL among blood leukocytes was 2-6 percent. LGL could be enriched to an average purity of 95 percent by combining discontinuous density gradient centrifugation with subsequent adsorptions of the low density fractions on monolayers of immobilized immune complexes. About 50 percent of LGL were found to be FcγR-bearing T cells (T(G)), forming low affinity rosettes with sheep erythrocytes at 4 degrees C. Only 10-20 percent of LGL formed high affinity rosettes with sheep erythrocytes at 29 degrees C. LGL could be enriched to a purity of more than 90 percent by depleting high affinity rosette-forming cells from low density Percoll fractions. LGL were only a subpopulation of T(G) cells, because some lymphocytes with conventional morphology also adhered to the immobilized immune complex monolayers and formed high affinity rosettes with sheep erythrocytes. Separation of these cells from LGL by discontinuous density gradient centrifugation indicated that they are not cytotoxic, suggesting a morphological and functional subdivision of T(G) cells. The verification in this study that virtually all human NK and K cells have a characteristic morphology adds a useful parameter to the monitoring of human lymphocytes, and the ability to purify these cells by simple physical procedures should be invaluable in their further characterization.

Differential Regulation of Chemokine Gene Expression by 15-Deoxy-Δ12,1412,14 Prostaglandin J2

“…The nonadherent PBMC was fractionated by a seven-step Percoll gradient as previously described (18), and the enriched monocyte populations (containing 65-85% of CD14 ϩ cells) were obtained at the very top of the gradient (top fraction). The cells were collected and washed twice with ice-cold PBS.…”

Variant lymphoproliferative disorder of granular lymphocytes (LDGL) following Hodgkin lymphoma

“…Large granular lymphocytes (LGL) account for approximately 10% of peripheral blood mononuclear cells in human [1]. Immunophenotypically, LGLs can be natural killer cells (CD3 À ) or T cells (CD3 + ).…”

In vitro modulation of human natural killer cell activity by interferon: Generation of adherent suppressor cells

“…We have recently demonstrated that a minor proportion of blood and tumour-associated NK cells kill autologous tumour cells freshly isolated from the same cancer patients (Uchida & Micksche, 1983a). Recent reports have indicated that human NK cells activity is strongly associated with a morphological subpopulation of lymphoid cells, termed large granular lymphocytes (LGL) (Timonen et al, 1981). Although LGL are not synonymous with NK cells, more than 50% of…”